Your guide to LEDs

LED is for light-emitting diode and is a semiconductor diode that emits incoherent narrow-spectrum light when electrically biased in the forward direction of the p-n junction. This effect is a form of electroluminescence.

An LED is usually a small area source, often with extra optics added to the chip that shapes its radiation pattern. The colour of the emitted light depends on the composition and condition of the semiconducting material used, and can be infrared, visible, or near-ultraviolet. An LED can be used as a standard household light source.

LEDs are found in all kinds of devices:

• digital clocks
• remote controls
• watches
• ‘on’ switches
• television screens
• traffic lights

LEDs are just tiny light bulbs that fit easily into an electrical circuit. But unlike ordinary incandescent bulbs, they have no filament and don’t get hot. They are illuminated solely by the movement of electrons in a semiconductor material.